Need assistance in selecting the right usb ttl cable

greetings, i believe i would need to obtain an usb ttl cable to successfully load an openwrt image to the ea7500v1. i need someone to help me validate i've selected the right cable. i believe either one should work, right? if none was right, can you please direct me to the right one? thanks.

1.8V USB To TTL Line USB Transfer Serial Line 1.8V Brush Line Download Line

FT232RL serial port module USB to TTL serial port small board 5V 3.3V 1.8V level Download the burn line

TTL-232R-RPI

FTDI all the way

FTDI cables (chips) from Aliexpress will most likely be fakes
CP2104 might be an alternative if you want something cheap though

hmm... does it really matter if the ftdi cables from alixpress could be fakes? i mean if a cable works then it is serving its function and utility, right?

love your work dave...

It could, and you cannot trust the output, )

I got this earlier this year... Haven't been using it much, but it works.

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...and if it doesn't? A CP2014 board/cable isn't much more expensive and is available outside .cn for example.

Whether fake matters to you or not depends... The issue @frollic points to is obviously not a problem on Linux for example. And I believe it was a temporary thing on Windows as well. And I suspect the fake chips have adapted to prevent such errors, simply by making the eeprom read-only.

I recently got a few of these cheap fakes. I must say I am impressed at how good the faking is. All the features I need have been implemented, and work AFAICS. Most importantly to me: The internal 3.3V regulator and level shifters work. So I can select 5V or 3.3V logic with a jumper setting, without frying anything (my modules don't have an 1.8V regulator, so they don't support that).

The issues I have noticed with the fakes is that they all have the same serial number (well known fake: A50285BI) and the eeprom cannot be modified. I can read the eeprom, and writes are successful, but nothing changes. So it's impossible to change that serial number, device IDs or pin configuration.

The fakes witll probably also have problems with high speed. I haven't tried anything higher than 115k2, which works perfectly.

So for me, who only need these for an occasional TTL console connection, the fakes are jut as good as the real thing. The only issue which might be considerde a problem is the non-unique serial, making it harder to distinguish different connections if you connect more than one of these to the same host. That doesn't matter to me.

But I don't recommend buying fakes if you can avoid it. The link @broly gave points to the real thing. It's much more expensive, but it's not like the price is prohibitive or insane. Personally I am just lazy.It's easier to buy on eBay, and impossible to find the real stuff there among all the fakes.

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digikey is a nice luxury. they give you cheap fedex shipping, and yes i agree 20 dollars can seem a little expensive.

however for how much i use this thing (when i use it), i don't find the cost to be prohibitive. i abuse the cable too. i'm on my second. i've probably unplugged/plugged this one 1000 times at least, same goes for the previous one that i had.

if you're gentle with the connectors, you would probably not need a second. they're built well.

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wow, looks like we have a winner. is this considered a genuine or still a fake?

DSD TECH SH-U09C5 USB to TTL UART Converter Cable with FTDI Chip Support 5V 3.3V 2.5V 1.8V TTL

No idea.

Doesn't require any drivers, or they auto installed over internet w/o user action required.

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i like the part where it's compatible with either 5v, 3.3v, 2.5v, or 1.8v. i understand it all boils down to a personal choice but i'm just not keen on the idea of de-soldering or soldering of additional components on the board to get the uart voltage right.

now my next task is to find out exactly what voltage uart the ea7500 uses because it's not clear to me after reading this post. was it 1.8v or 3.3v?

Hard to tell by looking at pictures. You'll only know when you see the serial number or try to modify the eeprom settings. And maybe not even then...

See https://softsolder.com/2016/09/02/counterfeit-ftdi-usb-serial-adapter-roundup/

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thanks for the link. sounds like 'caveat emptor.' i also read the comments and i think perhaps it may be prudent to explore the ch340g to avoid any licensing or counterfeit issue. for my purpose, i'm not planning on making any eeprom changes but only to tftp an openwrt image to a US version of ea7500v1.

I connected mine to a Linux box, to get the serial.
Searching for it on google, gave me zero hits.

Then again, when I searched for the one in the article you posted, there was only one hit - the article :wink:

Do you mean the genuine in the lsusb output shown, or the fake in the text below? The fake number should have plenty of hits.

FWIW, I have two fakes connected to my laptop right now:

root@miraculix:/tmp# grep -4 FTDI /sys/kernel/debug/usb/devices 

T:  Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 21 Spd=12   MxCh= 0
D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
P:  Vendor=0403 ProdID=6001 Rev= 6.00
S:  Manufacturer=FTDI
S:  Product=FT232R USB UART
S:  SerialNumber=A50285BI
C:* #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr= 90mA
I:* If#= 0 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=ftdi_sio
--

T:  Bus=01 Lev=01 Prnt=01 Port=02 Cnt=03 Dev#= 22 Spd=12   MxCh= 0
D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
P:  Vendor=0403 ProdID=6001 Rev= 6.00
S:  Manufacturer=FTDI
S:  Product=FT232R USB UART
S:  SerialNumber=A50285BI
C:* #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr= 90mA
I:* If#= 0 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=ftdi_sio

I read it wrong / not carefully enough.

My serial's different, so I would assume it's legit.

https://github.com/NetBSD/src/blob/trunk/sys/dev/usb/uchcom.c#L40 :slight_smile:

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thanks for the warning. it might be worse than fakes. :rofl: